Palestinians are celebrating on the streets as Israel is forced to declare a ceasefire - further evidence that the Arab revolutions have drastically changed the political landscape argues John Rees

All ceasefires in Gaza are temporary and unstable because the underlying problem, the continuing expropriation of Palestinian land by the Israeli state, continues. But each ceasefire marks a particular balance of forces which should be carefully examined.

This ceasefire was declared on the day that a bus bomb exploded in Tel Aviv, after a campaign in which rockets hit Tel Aviv for the first time, and when 75,000 Israeli troops were massed on the borders of Gaza ready for the order to invade to come from what is, even by the extraordinary standards of the state of Israel, a very right wing government.

So the question is how did a ceasefire get declared just at the moment when by all the ordinary laws of Israeli politics bombardment should have been followed by invasion. Rather like the Sherlock Holmes story Silver Blaze where the 'dog that didn't bark in the night' is the vital clue, this is all about something that didn't happen when it should have done.

The vital difference is that Operation Cast Lead in 2008-2009 happened before the Arab Revolutions and the current misnamed Operation Pillar of Defence has happened in a political landscape still being transformed by those revolutions.

The Arab revolutions have weakened the political position of the Israeli state in a number of ways. Mubarak's Egypt was absolutely loyal to US foreign policy and therefore absolutely unable to make even mild gestures of support for the Palestinians. Mohammed Morsi, the Muslim Brotherhood President of Egypt, has played a different hand. He knows that a powerful current of Palestinian solidarity runs through the continuing Egyptian revolution and that it is simply politically impossible to continue the Mubarak line.

Thus the Rafah crossing was opened, the Egyptian ambassador recalled, the Israeli envoy kicked out, pro-Palestinian declarations issued. A similar change in stance could be seen in Tunisia.

Turkey was still a supporter of Israel at the time of Operation Cast Lead. But the attack on the Turkish registered Mavi Marmara Gaza solidarity vessel marked a breach. Even more fundamentally the Turkish state has broken, at least at the level of rhetoric, with support for Israel as the price of playing an active role in trying to shape the outcome of the Arab revolutions.

Without this context we would never have heard Prime Minister Erdogan say that 'Israel is a terrorist state'. But of course he linked this with calls for intervention in Syria saying that the West is ignoring the plight of Muslims in both Palestine and Israel.

The crisis of imperial rule in the Middle East also worked towards a ceasefire. The US, Britain and other Western powers will never move away from support for the state of Israel because it is the armed guardian of their interests in the region. But the on-going Syrian civil war and the strategic necessity of coping with Iran make them nervous about an Israeli ground invasion.

Put simply, if a crisis in Gaza inflames anti-Western opinion in the Middle East and fuels anti-war protests around the globe then action in Syria and against Iran become more difficult. And these issues are more important to the West than Gaza. The protests in Jordan during the Gaza bombing underlined this problem for the West.

Egypt remains the most important centre in the Arab world and so Cairo became the centre of diplomacy. Morsi is of course the most conservative embodiment of the Egyptian revolution. He has not torn up the peace treaty with Israel and the state he heads still depends on US military aid $1.3 billion annually. Thus a negotiated ceasefire suited Morsi as much as it suited the US.

This is the axis which brought the fighting to a halt. Israeli leader Netanyahu was rewarded with a call from President Obama promising more money for the Iron Dome missile defence system.

So Hamas can claim that just at the moment when it hit Israel harder than it has ever been hit before the Israelis were prevented from hitting back as hard as they have done before. But the conditions that produced this outcome are more to do with the wider intersection of imperial power and the Arab revolutions than they are to do with the internal effectiveness of resistance in Gaza, however vital and necessary that remains.

And dangers are still present. Firstly, Israel may not allow the ceasefire to stand. Secondly, the siege of Gaza has not been lifted. Thirdly, Israel wanted to hit Hamas now because it fears its reaction when it strikes at Iran in the future. The Israeli reaction to a ceasefire it does not like will be to press the case for an attack on Iran even more insistently.

William Hague has just recognised the Syrian pro-western opposition as the official government of Syria. That paves the way for greater covert arming of those sections of the opposition and raises the possibility of more overt forms of intervention once more.

The parallelogram of forces has given Gaza some respite. That is important. Some 160 Gazans lost their lives in recent days. It is some comfort that the figure is not as great as the nearly 1,500 who died as a result of Operation Cast Lead.

The anti-war movement now has a chance to assess the strengths and weaknesses of the war-mongers. But they are planning their next moves as we do so. And we should be doing likewise.